Photographic stripping film



Sept- 11, 1 3 c. R; FoRb cE ET-AL 1,973,476

PHOTOGRAPHIC STRIPPING FILM Filed Dec. 15, 1933 5kbler permeable layer of cellulose 4'Sensifive layer aliphafic acid ester of low acyl value K (Hydrolyzed cellulose aceldle propionale) -supporflPaper) ZV-Sfrhaping layer(8oluble gelaflne I Y J ordexlrine amniotic ClzmlesRFordycemMaz'lblm dam-M1 Patented Sept. 11; 1934 PHOTOGRAPHIC STRIPPING FILM Charles R. Fordyce and Martti Salo, Rochester,

N. Y., assignors to Eastman Kodak Company, Rochester, N. Y., a corporation of New York Application December 15, 1933, Serial No. 702,560

' 6 Claims. (01. 95-9) This invention relates to photographic stripping film, that is to say, to a photographic film in which the sensitive layer is carried on a temporary support from which it may be stripped during or after usef In accordance with the present invention the sensitive layer is carried on a water permeable layer or support to which it is permanently attached and which is in turn carried on a support 10 from which it is stripped and the invention consists in the use, in a stripping film, of a particular material as the permanent support.

Reference will now be made to the accompanying drawing in which the single figure shows on'an exaggerated scale a section of a film embodying our invention.

It 'is to be understood that while we have shown and described in some detail a particular embodiment of the temporary support and of other parts, this has been for the'purpose of making a complete disclosure of a preferred and operative embodiment and that we do not limit ourselves to the structures shown, numerous modifications and equivalents being possible and contemplated as within the scope of the invention.

In the drawing the reference character 1 designates the temporary support which may be of paper and which may or'may not be water permeable. This carries an adhesive layer 2, which may be of readily soluble gelatine or compositions comprising chiefly water soluble dextrine, and over this a layer 3 which is water permeable but not water soluble and, finally, a photographic emulsion 4, which is applied by usual photographic coating methods. The particular stripping layer is not of importance.

During the process of development, which may require only two or three minutes, the solution penetrates layers 3 and 4, and may also penetrate the layer 1, and softens or dissolves the layer 2 so that the layer 3 with the emulsion 4 adherent to it may be easily stripped from the support 1, and may be dried or may be placed on a glass plate or other surface for further use.

We have found that as a material for the layer 3, cellulose aliphatic esters of low acyl content are eminently suitable. While they are readily penetrated by water, they are not distorted or disintegrated by the action of the water or other ordinary photographic solution and after drying constitute firm, smooth photographic records. Cellulose acetate of an acetyl value less than 36% may be used satisfactorily. The range between 33% and 36% is most practical from certain standpoints, because of difliculties in coating when the content is less than 33%. However, the permeability increases as the acetyl content grows less so that the film has increased advantages in the lower range.

' Another useful material is hydrolyzed cellulose acetate propionate, hydrolyzed to as low as 26% acetyl and from 4 to 5% propionyl. In general, We may use cellulose acetate of low acetyl value or any cellulosic mixed ester of low acyl value and particularly one containing acetyl groups in excess over the other acyl radicals.

While the methods of making the film do not constitute any part of the present invention, the layers just described may be formed by coating from solutions in which the solvents may be mixtures of acetone and methyl alcohol, ethylene chloride and methyl alcohol, or acetone and water; or ethylene glycol monomethyl ether, or mixtures of ethylene glycol monomethyl ether with ethylene dichloride and methyl alcohol. If the cellulose acetate composition is to be coated directly upon the water soluble layer, it will be necessary to use solvents which will not dissolve the latter. This may be coated directly upon the 30 paper support 1, previously coated with the water-soluble coating 2, or it may be formed as a separate film and laminated on the paper support.

It is to be understood that the disclosure herein as is by way of example and that we consider as included in our invention any modifications and equivalents within the scope of the appended claims. J

Having thus described our invention, what we claim as new and desire to secure by Letters Patent is:

1. A stripping photographic film comprising, in order, a temporary support, a stripping layer,

a water permeable layer and a photographic emulsion layer, the photographic layer being permanently carried by the permeable layer and. the permeable layer comprising a cellulose aliphatic acid ester having a low acyl content.

2. A stripping photographic film comprising, in order, a temporary support, a soluble layer, a water permeable layer and a photographic emulsion layer, the photographic layer being permanently carried by the permeable layer and the permeable layer comprising a cellulose acetate having an acyl content less than 36%.

3. A stripping photographic film comprising, in order, a temporary support,a water soluble layer, a water permeable layer and a photographic emulsion layer, the photographic layer being-11b permanently carried by the permeable layer and the permeable layer comprising a cellulose aliphatic acid mixed ester of low acyl value containing acetyl groups in excess over any other acyl radicals.

- v 4. A stripping photographic film comprising,

5. A stripping photographic film comprising,

in order, a temporary support, a soluble layer, a

emma water permeable layer and a photographic emulsion layer, the photographic layer being permanently carried by the permeable layer and the permeable layer comprising a cellulose acetate propionate having an acyl value below 36% and containing more acetyl than propionyl groups.

6. Astripping photographic film comprising, in order, a temporary support, a soluble layer, a water permeable layer and a photographic emulsion layer, the photographic layer being permanently carried by the permeable layer and the permeable layer comprising a cellulose acetate p'ropionate containing less than 30% acetyl groups and less than 5% propionyl groups.

CHARLES R. FORDYCE.

MARTTI SALO. 

